I frequently keep myself occupied on flights by working on my laptop. I hate the limited battery life, which sometimes limits me to less than an hour.

Recently, I purchased a digital camera which uses CompactFlash memory. It is a very small (1" x 1") card which you put in the camera. You then put it into an adapter and into a PCMCIA slot.

This card comes in various memory sizes, and they aren't very expensive. I see a price here for a 32M card for $89.95.

OK, so that is comparable to the price of a battery pack. The difference is, this thing only weighs like 2 oz.

I work on a lot of different files, so just setting the hard drive to timeout after a minute wasn't the answer because it would no sooner spin down before I needed another hard disk access.

Using one of these cards, I moved all my work to the card. I barely used my hard drive, which really extended battery life. I got a little over 2 1/2 hours instead of my normal 1.

There are some caveats of course. You need be sure to move the files off this card back to your hard disk when you are done (I waited until I was on AC power).

Naturally, this is more work that simply plugging in another battery, however the trade-off in not having to charge and carry another battery was well worth it to me.

Years ago in the DOS world we used to create a RAMDRIVE, and accomplish much the same thing. RAM takes a fraction of the power of a hard drive, and is faster by orders of magnitude.

Another strategy: while attached to AC power open the files and programs you intend to work on. Then put the latop in SUSPEND mode. When it wakes up, you won't need to wait as long or waste as much power bring up all the programs and files from scratch.